1. Field of the Invention
The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly to a weight-reduced liquid crystal display device and a method of manufacturing the same.
2. Description of the Related Art
To achieve the goals of small size and low power consumption, flat panel display devices such as LCD (Liquid Crystal Display), PDP (Plasma Display Panel), ELD (Electroluminescent Display), and VFD (Vacuum Fluorescent Display) have been introduced. In these flat panel display devices, the LCD has been most actively researched recently because of good image quality and low power consumption in spite of some disadvantages. Although portable televisions and notebook computers having the LCD have been marketed, there are various problems which need to be solved. Because televisions and computers have become portable electronic products, the reduction of the size and weight is one of the important goals in the LCD research.
There are various methods to reduce the size and weight of the LCD. It is, however, difficult to reduce numbers of the components of the LCD. In addition, the weight and size of the components are so small that the weight and size of the components can hardly be reduced further. Fortunately, the weight of the glass substrate which is one of the basic components of the LCD can be reduced further. Moreover, the weight reduction of the glass substrate becomes important because it occupies a large portion of the total weight of the LCD.
In the conventional technique, transparent glass is used for the substrates in manufacturing the liquid crystal display. Since conventionally used glass is comparatively thick, it is protected against physical or thermal impacts during processing procedure. To reduce the weight of LCD devices, a single substrate which is 0.6 mm in thickness is adopted. However, if a thin substrate less than 0.6 mm in thickness is used from the initial stage, the yield will decrease due to damage or deformation. For the lower substrate manufacturing and the liquid crystal filling processes, the process of heating or cooling between 200–300° C. occurs more than ten times. In addition, a high-speed rotation process for the rinsing or coating process is repeated for several times. For the foregoing limitations, the glass substrates should not be too thin before the liquid crystal is injected into the space between two glass substrates to form an LCD cell.
The manufacture process of a conventional LCD device is shown in FIG. 1. In step 101, the upper and lower substrates are manufactured. In step 102, the upper and lower substrates are oppositely positioned and joined to form an LCD cell. In step 103, the liquid crystal is injected into the space between the upper and lower substrates. In step 104, a lapping process is conducted to reduce the thickness of the upper and lower substrates. In step 105, the outer surfaces of the upper and lower substrates are polished. In step 106, a pair of optical films are attached on the upper and lower substrates, respectively. After step 104, the outer surfaces of the glass substrates become quite rough. Therefore, in this conventional method, the lapped thin glass substrates will be polished to smooth the surfaces of the glass substrates, and then the optical films are attached to the substrates by an adhesive layer. However, in the industrial manufacturing process, more manufacturing steps lead to higher possibility of producing defect products and increasing manufacturing cost. Therefore, there exits a need for a simplified manufacturing process which can be used to reduce the weight of glass substrates thereby reducing the manufacturing cost and the failure rate of the products.